A tidal current turbine is a device for harnessing energy from marine currents, and functions in a manner similar to a wind turbine. A group of tidal current turbines distributed in a site in ocean is called a tidal turbine farm. Among all tidal current energy extraction schemes, turbine farm is regarded as among the most promising turbine configurations; in fact, of turbine farms are extensively employed in the wind power industry. Wind farm planning and modeling approaches cannot be fully transferred to tidal farms, however, because of the complexities involved in modeling the underwater tidal turbine. This study develops a framework for planning a tidal turbine farm system with vertical axis tidal current turbines. This framework is intended to be used by energy planners in the early design stage. An approach for selecting the optimal design among alternative tidal turbine farm designs is proposed whereby the attractiveness of the alternatives is evaluated based on cost effectiveness. Where possible, experience gained from analysis of existing offshore wind farms is applied. The state of the art of tidal turbine design and wind farm planning are reviewed, and a planning framework for selecting the optimal tidal farm design is provided by identifying the important mathematical modeling procedures and elements. Considering the particular design of the vertical axis tidal turbine, a simplified relationship of turbine distribution and turbine farm efficiency is developed. As a case study, numerical simulation results are presented for environmental conditions offshore of British Columbia, Canada.